1. Field of the Invention
The present invention relates to a treadmill and, more particularly, to a treadmill with an adjustable shock-absorbing structure.
2. Description of the Related Art
A conventional treadmill in accordance with the prior art shown in FIGS. 1-3 comprises a frame 20, a support plate 21 mounted on and located above the frame 20, a belt 22 mounted around the support plate 21, and a plurality of vibration absorbers 23 mounted between the frame 20 and the support plate 21 by a plurality of bolts 24. Each of the vibration absorbers 23 has a cylindrical shape. In operation, when the user steps on the belt 22, the support plate 21 is subjected to a downward force. At this time, the vibration absorbers 23 apply a reaction to the support plate 21 so as to provide a shock-absorbing function to the support plate 21. However, each of the vibration absorbers 23 has a fixed elasticity that cannot be adjusted according to the user's requirement. In addition, the vibration absorbers 23 are easily deflected and distorted due to an unevenly distributed force applied by the user's downward pressure so that the vibration absorbers 23 are easily worn or torn during a long-term utilization, thereby decreasing the shock-absorbing function.